| Global warming is the increase in the average | | | | conclusions, and a few individual scientists |
| temperature of the Earth's near-surface air | | | | also disagree with parts of them. |
| and oceans in recent decades and its | | | | |
| projected continuation. | | | | An increase in global temperatures can in |
| | | | turn cause other changes, including sea level |
| Global average air temperature near the | | | | rise, and changes in the amount and pattern |
| Earth's surface rose 0.74 ± 0.18 °C | | | | of precipitation resulting in floods and |
| during the past century. The | | | | drought. There may also be changes in the |
| Intergovernmental Panel on Climate Change | | | | frequency and intensity of extreme weather |
| (IPCC) concludes, "most of the observed | | | | events, though it is difficult to connect |
| increase in globally averaged temperatures | | | | specific events to global warming. Other |
| since the mid-20th century is very likely due | | | | effects may include changes in agricultural |
| to the observed increase in anthropogenic | | | | yields, glacier retreat, reduced summer |
| greenhouse gas concentrations," which leads | | | | streamflows, species extinctions and |
| to warming of the surface and lower | | | | increases in the ranges of disease vectors. |
| atmosphere by increasing the greenhouse | | | | |
| effect. Natural phenomena such as solar | | | | The term "global warming" is a specific |
| variation combined with volcanoes have | | | | example of the broader term climate change, |
| probably had a small warming effect from | | | | which can also refer to global cooling. In |
| pre-industrial times to 1950, but a small | | | | common usage the term refers to recent |
| cooling effect since 1950. | | | | warming and implies a human influence. The |
| | | | United Nations Framework Convention on |
| These basic conclusions have been endorsed by | | | | Climate Change (UNFCCC) uses the term |
| at least 30 scientific societies and | | | | "climate change" for human-caused change, and |
| academies of science, including all of the | | | | "climate variability" for other changes. The |
| national academies of science of the major | | | | term "anthropogenic climate change" is |
| industrialized countries. The American | | | | sometimes used when focusing on human-induced |
| Association of Petroleum Geologists is the | | | | changes. |
| only scientific society that rejects these | | | | |